/// 根据模板，使用此法分析的方法输出字符串
/// </summary>
/// <param name="template"></param>
/// <param name="dt"></param>
/// <returns></returns>
public static string Render(string template, DataTable dt)
{
StringBuilder sb = new StringBuilder(1000);
List<string> arr = new List<string>();
List<string> columns = new List<string>();
int previousEndIndex = 0;
//找到{xxx}
int startIndex = template.IndexOf('{');
int endIndex = template.IndexOf('}');
while (startIndex != -1)
{
//存储上一个}和现在搜索到的{之间的字符串，如果是第一次搜索到{，那么previousEndIndex=0则存储的是字符串起始到第一个{之间的字符串
arr.Add(template.Substring(previousEndIndex, startIndex - previousEndIndex));
//存储列名
columns.Add(template.Substring(startIndex + 1, endIndex - startIndex - 1));
startIndex++;
endIndex++;
previousEndIndex = endIndex;
startIndex = template.IndexOf('{', startIndex);
endIndex = template.IndexOf('}', endIndex);
}
//如果模板不是以}结尾，说明后面还有字符串
if (previousEndIndex < template.Length)
{
arr.Add(template.Substring(previousEndIndex));
}
//方法执行到此处，arr.Length==columns.Length或者arr.Length==columns.Length+1
int i;
foreach (DataRow row in dt.Rows)
{
i = 0;
for (; i < columns.Count; i++)
{
sb.Append(arr[i]);
sb.Append(row[columns[i]].ToString());
}
if (i < arr.Count)
{
sb.Append(arr[i]);
}
}
return sb.ToString();
}
/// <summary>
/// 根据模板，使用正则匹配然后替换输出字符串
/// </summary>
/// <param name="template"></param>
/// <param name="dt"></param>
/// <returns></returns>
public static string RenderTemplate(string template, DataTable dt)
{
StringBuilder sb = new StringBuilder(1000);
MatchCollection matches = reg.Matches(template);
string rowStr = template;
foreach (DataRow row in dt.Rows)
{
rowStr = template;
foreach (Match match in matches)
{
rowStr = rowStr.Replace(match.Value, row[match.Groups[1].Value].ToString());
}
sb.Append(rowStr);
sb.Append("\n");
}
return sb.ToString();
}
create table links
(
siteurl varchar(100),
sitename varchar(100)
)
declare @i int
set @i=0
while(@i<100000)
begin
insert links values('http://www.baidu.com','百度')
set @i=@i+1
end
第一种：
后台代码如下：
public override void ProcessRequest(HttpContext context)
{
Stopwatch watch = new Stopwatch();
watch.Start();
base.ProcessRequest(context);
watch.Stop();
HttpContext.Current.Response.Write(watch.Elapsed.ToString());
}
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
rpt.DataSource = GetTable();
rpt.DataBind();
}
}
public DataTable GetTable()
{
using (SqlConnection conn = new SqlConnection("Data Source=wh189\\sqlexpress;Initial Catalog=A;User ID=sa;Password=sa"))
{
DataTable dt = new DataTable();
SqlDataAdapter sda = new SqlDataAdapter("select top 50000 * from dbo.links", conn);
sda.Fill(dt);
return dt;
}
}
前台代码如下：
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="TestWeb._Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div style="display: none;">
<asp:Repeater ID="rpt" runat="server">
<ItemTemplate>
<a href='<%# ((System.Data.DataRowView)Container.DataItem)["siteurl"] %>'>
<%# ((System.Data.DataRowView)Container.DataItem)["sitename"]%></a>
</ItemTemplate>
</asp:Repeater>
</div>
<asp:Button ID="Button1" runat="server" Text="Button" />
</form>
</body>
</html>
时间大概为1秒左右，如果没有使用System.Data.DataRowView，使用Eval，则时间大概在1.2秒左右
第二种：
前台代码如下：
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="TestWeb._Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div style="display: none;">
<%System.Data.DataTable dt = GetTable();
foreach (System.Data.DataRow dr in dt.Rows)
{ %>
<a href='<%=dr["siteurl"] %>'>
<%=dr["sitename"]%></a>
<%}
%>
</div>
<asp:Button ID="Button1" runat="server" Text="Button" />
</form>
</body>
</html>
后台代码如下：
public override void ProcessRequest(HttpContext context)
{
Stopwatch watch = new Stopwatch();
watch.Start();
base.ProcessRequest(context);
watch.Stop();
HttpContext.Current.Response.Write(watch.Elapsed.ToString());
}
protected void Page_Load(object sender, EventArgs e)
{
}
public DataTable GetTable()
{
using (SqlConnection conn = new SqlConnection("Data Source=wh189\\sqlexpress;Initial Catalog=A;User ID=sa;Password=sa"))
{
DataTable dt = new DataTable();
SqlDataAdapter sda = new SqlDataAdapter("select top 50000 * from dbo.links", conn);
sda.Fill(dt);
return dt;
}
}
时间大概为0.2秒左右
第三种：
前台代码如下：
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="TestWeb._Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div style="display:none;">
<%=Tool.Render("<a href='{siteurl}'>{sitename}</a>",GetTable()) %>
</div>
<asp:Button ID="Button1" runat="server" Text="Button" />
</form>
</body>
</html>
后台代码如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Collections;
using System.Data.SqlClient;
using System.Diagnostics;
using System.Text;
using System.Text.RegularExpressions;
namespace TestWeb
{
public partial class _Default : System.Web.UI.Page
{
public override void ProcessRequest(HttpContext context)
{
Stopwatch watch = new Stopwatch();
watch.Start();
base.ProcessRequest(context);
watch.Stop();
HttpContext.Current.Response.Write(watch.Elapsed.ToString());
}
protected void Page_Load(object sender, EventArgs e)
{
}
public DataTable GetTable()
{
using (SqlConnection conn = new SqlConnection("Data Source=wh189\\sqlexpress;Initial Catalog=A;User ID=sa;Password=sa"))
{
DataTable dt = new DataTable();
SqlDataAdapter sda = new SqlDataAdapter("select top 50000 * from dbo.links", conn);
sda.Fill(dt);
return dt;
}
}
}
}
/// <summary>
///Tool 的摘要说明
/// </summary>
public class Tool
{
/// <summary>
/// 根据模板，使用此法分析的方法输出字符串
/// </summary>
/// <param name="template"></param>
/// <param name="dt"></param>
/// <returns></returns>
public static string Render(string template, DataTable dt)
{
StringBuilder sb = new StringBuilder(1000);
List<string> arr = new List<string>();
List<string> columns = new List<string>();
int previousEndIndex = 0;
//找到{xxx}
int startIndex = template.IndexOf('{');
int endIndex = template.IndexOf('}');
while (startIndex != -1)
{
//存储上一个}和现在搜索到的{之间的字符串，如果是第一次搜索到{，那么previousEndIndex=0则存储的是字符串起始到第一个{之间的字符串
arr.Add(template.Substring(previousEndIndex, startIndex - previousEndIndex));
//存储列名
columns.Add(template.Substring(startIndex + 1, endIndex - startIndex - 1));
startIndex++;
endIndex++;
previousEndIndex = endIndex;
startIndex = template.IndexOf('{', startIndex);
endIndex = template.IndexOf('}', endIndex);
}
//如果模板不是以}结尾，说明后面还有字符串
if (previousEndIndex < template.Length)
{
arr.Add(template.Substring(previousEndIndex));
}
//方法执行到此处，arr.Length==columns.Length或者arr.Length==columns.Length+1
int i;
foreach (DataRow row in dt.Rows)
{
i = 0;
for (; i < columns.Count; i++)
{
sb.Append(arr[i]);
sb.Append(row[columns[i]].ToString());
}
if (i < arr.Count)
{
sb.Append(arr[i]);
}
}
return sb.ToString();
}
}
时间大概也为0.2秒左右
如果把查询数据量增加到10万，发现第二种方法比第三种要快几秒 。但是如果将第三种方法中的Render方法做如下改进，则两者速度又差不多了：
public static string Render(string template, DataTable dt)
{
//使用HttpResponse 直接输出，而不使用StringBuilder
HttpResponse res = HttpContext.Current.Response;
List<string> arr = new List<string>();
List<string> columns = new List<string>();
int previousEndIndex = 0;
//找到{xxx}
int startIndex = template.IndexOf('{');
int endIndex = template.IndexOf('}');
while (startIndex != -1)
{
//存储上一个}和现在搜索到的{之间的字符串，如果是第一次搜索到{，那么previousEndIndex=0则存储的是字符串起始到第一个{之间的字符串
arr.Add(template.Substring(previousEndIndex, startIndex - previousEndIndex));
//存储列名
columns.Add(template.Substring(startIndex + 1, endIndex - startIndex - 1));
startIndex++;
endIndex++;
previousEndIndex = endIndex;
startIndex = template.IndexOf('{', startIndex);
endIndex = template.IndexOf('}', endIndex);
}
//如果模板不是以}结尾，说明后面还有字符串
if (previousEndIndex < template.Length)
{
arr.Add(template.Substring(previousEndIndex));
}
//方法执行到此处，arr.Length==columns.Length或者arr.Length==columns.Length+1
int i;
foreach (DataRow row in dt.Rows)
{
i = 0;
for (; i < columns.Count; i++)
{
res.Write(arr[i]);
res.Write(row[columns[i]].ToString());
}
if (i < arr.Count)
{
res.Write(arr[i]);
}
}
return "";
}